Recently, a tablet terminal provided with a display screen which is also used as an input unit based on a touch panel scheme or the like has been rapidly distributed. Since the tablet terminal has a widget or a desktop as an interface, and it is easy to visually understand an operation method, users can readily use the tablet terminal as compared with a personal computer on which an input operation is performed via a keyboard or a mouse.
For example, a touch sensitive device which reads data belonging to a touch input relating to a multi-point sensing device from the multi-point sensing device such as a multi-point touch screen and identifies a multi-point gesture based on the data from the multi-point sensing device has been proposed (see Patent Literature 1, for example).
Generally, multiple operation target objects to be operated by a user are arranged in various orientations on a screen of the tablet terminal. The individual operation target objects are reproduced content such as a video image and a stationary image, e-mails and messages received from other users, and the like. It is necessary for the user to individually perform a rotation operation on a tablet terminal main body in order to display a desired operation target object so as to face the user. In the case of a tablet terminal with an A4 or A5 size, it is easy to perform the rotation operation. In the case of a large screen of about several tens of inches, however, performing the rotation operation on the tablet terminal every time a single user operates the operation target object is a nuisance for the user.
In addition, a use state in which a plurality of users individually perform operations on operation target objects in a tablet terminal with a large screen at the same time can be also considered.
For example, a tablet terminal which identifies an area between a right arm and a left arm when a proximity sensor detects a position, at which a user is present, at a side edge of the terminal and performs mapping in a touch point area of the user has been proposed (see Non Patent Literature 1, for example). The tablet terminal can be designed such that another user cannot perform certain operations such as an operation for rotating an operation target object, which is being operated by a certain user, in a direction in which the operation target object faces the user themselves by setting an operation right of each user for each operation target object or inhibiting additional user participation in advance when the tablet terminal detects a plurality of users.
As the use state in which a plurality of users commonly use the tablet terminal with the large screen, however, there may also be a case in which the users exchange operation target objects to perform cooperative work as well as the aforementioned case in which the users individually perform operations on the operation target objects. It is difficult to realize cooperative work if a touch point area occupied by each user is set and each user performs operations on the operation target objects, operation rights for which have been provided, in the individual area.
In addition, if a GUI displayed on the screen of the terminal is constant regardless of a distance from a user to the screen or a user state, there is a problem in that the size of information shown on the screen is excessively small and cannot be well understood by a user who is located at a distant position, or a problem in that an amount of information shown on the screen is small even though the user is positioned at a nearby position. Similarly, if input means for allowing the user to operate the terminal is constant regardless of the distance from the user to the screen or the user state, the user cannot perform any operations since there is no remote controller even though the user is positioned at a nearby position to the terminal, or the user is required to approach the terminal in order to operate the touch panel, which is inconvenient.
In addition, according to a conventional subject display system, an image of an actual object is displayed on the screen without consideration of real size information thereof. For this reason, there is a problem in that the size of the object displayed varies in accordance with a size or resolution (dpi) of the screen.
In addition, when movie content of a plurality of sources is simultaneously displayed on the screen in a display system in a parallel manner or in a superimposed manner, a magnitude relationship between the simultaneously displayed images is not correctly displayed, sizes and positions of corresponding areas for the images are not adjusted, and therefore, an image which cannot be easily viewed by the user is obtained.
In addition, since the user cannot easily view the screen if a direction of the screen of the terminal or the like which is provided with a rotation mechanism is changed, it is necessary to rotate the display screen.